Implement our own GLThread for VR Shell.

chrome/browser/android/vr_shell/vr_shell.cc

Index: chrome/browser/android/vr_shell/vr_shell.cc
diff --git a/chrome/browser/android/vr_shell/vr_shell.cc b/chrome/browser/android/vr_shell/vr_shell.cc
index 8fad473cc54708ffc5cedc0da52b4d5bcb9dd974..d9cbb274bed26298813a7463e7b9e2297b4fcd11 100644
--- a/chrome/browser/android/vr_shell/vr_shell.cc
+++ b/chrome/browser/android/vr_shell/vr_shell.cc
@@ -5,15 +5,15 @@
 #include "chrome/browser/android/vr_shell/vr_shell.h"
 
 #include "base/metrics/histogram_macros.h"
-#include "chrome/browser/android/vr_shell/ui_elements.h"
+#include "base/threading/platform_thread.h"
+#include "base/threading/thread.h"
+#include "base/threading/thread_restrictions.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/android/vr_shell/ui_interface.h"
-#include "chrome/browser/android/vr_shell/ui_scene.h"
 #include "chrome/browser/android/vr_shell/vr_compositor.h"
-#include "chrome/browser/android/vr_shell/vr_controller.h"
-#include "chrome/browser/android/vr_shell/vr_gl_util.h"
 #include "chrome/browser/android/vr_shell/vr_input_manager.h"
 #include "chrome/browser/android/vr_shell/vr_shell_delegate.h"
-#include "chrome/browser/android/vr_shell/vr_shell_renderer.h"
+#include "chrome/browser/android/vr_shell/vr_shell_gl.h"
 #include "chrome/browser/android/vr_shell/vr_usage_monitor.h"
 #include "chrome/browser/android/vr_shell/vr_web_contents_observer.h"
 #include "content/public/browser/navigation_controller.h"
@@ -29,124 +29,65 @@
 #include "ui/base/page_transition_types.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
-#include "ui/gl/gl_bindings.h"
-#include "ui/gl/init/gl_factory.h"
 
 using base::android::JavaParamRef;
+using base::android::JavaRef;
 
 namespace vr_shell {
 
 namespace {
-// Constant taken from treasure_hunt demo.
-static constexpr long kPredictionTimeWithoutVsyncNanos = 50000000;
-
-static constexpr float kZNear = 0.1f;
-static constexpr float kZFar = 1000.0f;
-
-// Screen angle in degrees. 0 = vertical, positive = top closer.
-static constexpr float kDesktopScreenTiltDefault = 0;
-
-static constexpr float kReticleWidth = 0.025f;
-static constexpr float kReticleHeight = 0.025f;
-
-static constexpr float kLaserWidth = 0.01f;
-
-// Angle (radians) the beam down from the controller axis, for wrist comfort.
-static constexpr float kErgoAngleOffset = 0.26f;
-
-static constexpr gvr::Vec3f kOrigin = {0.0f, 0.0f, 0.0f};
-
-// In lieu of an elbow model, we assume a position for the user's hand.
-// TODO(mthiesse): Handedness options.
-static constexpr gvr::Vec3f kHandPosition = {0.2f, -0.5f, -0.2f};
-
-// If there is no content quad, and the reticle isn't hitting another element,
-// draw the reticle at this distance.
-static constexpr float kDefaultReticleDistance = 2.0f;
-
-// Fraction of the distance to the object the cursor is drawn at to avoid
-// rounding errors drawing the cursor behind the object.
-static constexpr float kReticleOffset = 0.99f;
-
-// Limit the rendering distance of the reticle to the distance to a corner of
-// the content quad, times this value. This lets the rendering distance
-// adjust according to content quad placement.
-static constexpr float kReticleDistanceMultiplier = 1.5f;
-
-// GVR buffer indices for use with viewport->SetSourceBufferIndex
-// or frame.BindBuffer. We use one for world content (with reprojection)
-// including main VrShell and WebVR content plus world-space UI.
-// The headlocked buffer is for UI that should not use reprojection.
-static constexpr int kFramePrimaryBuffer = 0;
-static constexpr int kFrameHeadlockedBuffer = 1;
-
-// Pixel dimensions and field of view for the head-locked content. This
-// is currently sized to fit the WebVR "insecure transport" warnings,
-// adjust it as needed if there is additional content.
-static constexpr gvr::Sizei kHeadlockedBufferDimensions = {1024, 1024};
-static constexpr gvr::Rectf kHeadlockedBufferFov = {20.f, 20.f, 20.f, 20.f};
-
-// The GVR viewport list has two entries (left eye and right eye) for each
-// GVR buffer.
-static constexpr int kViewportListPrimaryOffset = 0;
-static constexpr int kViewportListHeadlockedOffset = 2;
-
-// Magic numbers used to mark valid pose index values encoded in frame
-// data. Must match the magic numbers used in blink's VRDisplay.cpp.
-static constexpr std::array<uint8_t, 2> kWebVrPosePixelMagicNumbers{{42, 142}};
-
 vr_shell::VrShell* g_instance;
 
 static const char kVrShellUIURL[] = "chrome://vr-shell-ui";
 
-float Distance(const gvr::Vec3f& vec1, const gvr::Vec3f& vec2) {
-  float xdiff = (vec1.x - vec2.x);
-  float ydiff = (vec1.y - vec2.y);
-  float zdiff = (vec1.z - vec2.z);
-  float scale = xdiff * xdiff + ydiff * ydiff + zdiff * zdiff;
-  return std::sqrt(scale);
-}
-
-// Generate a quaternion representing the rotation from the negative Z axis
-// (0, 0, -1) to a specified vector. This is an optimized version of a more
-// general vector-to-vector calculation.
-gvr::Quatf GetRotationFromZAxis(gvr::Vec3f vec) {
-  vr_shell::NormalizeVector(vec);
-  gvr::Quatf quat;
-  quat.qw = 1.0f - vec.z;
-  if (quat.qw < 1e-6f) {
-    // Degenerate case: vectors are exactly opposite. Replace by an
-    // arbitrary 180 degree rotation to avoid invalid normalization.
-    quat.qx = 1.0f;
-    quat.qy = 0.0f;
-    quat.qz = 0.0f;
-    quat.qw = 0.0f;
-  } else {
-    quat.qx = vec.y;
-    quat.qy = -vec.x;
-    quat.qz = 0.0f;
-    vr_shell::NormalizeQuat(quat);
+class GLThread : public base::Thread {
+ public:
+  GLThread(VrShell* vr_shell, base::WeakPtr<VrShell> weak_vr_shell,
+           base::WeakPtr<VrInputManager> content_input_manager,
+           base::WeakPtr<VrInputManager> ui_input_manager,
+           scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner,
+           gvr_context* gvr_api)
+      : base::Thread("VrShellGL"),
+        vr_shell_(vr_shell),
+        weak_vr_shell_(weak_vr_shell),
+        content_input_manager_(content_input_manager),
+        ui_input_manager_(ui_input_manager),
+        main_thread_task_runner_(std::move(main_thread_task_runner)),
+        gvr_api_(gvr_api) {}
+
+  base::WeakPtr<VrShellGl> GetVrShellGl() { return weak_vr_shell_gl_; }
+  VrShellGl* GetVrShellGlUnsafe() { return vr_shell_gl_.get(); }
+  void StopRenderLoop() {
+    vr_shell_gl_.reset();
+  }
+
+ protected:
+  void Init() override {
+    vr_shell_gl_.reset(new VrShellGl(vr_shell_,
+                                     std::move(weak_vr_shell_),
+                                     std::move(content_input_manager_),
+                                     std::move(ui_input_manager_),
+                                     std::move(main_thread_task_runner_),
+                                     gvr_api_));
+    weak_vr_shell_gl_ = vr_shell_gl_->GetWeakPtr();
+    if (!vr_shell_gl_->Initialize()) {
+      vr_shell_gl_.reset();
+    }
   }
-  return quat;
-}
 
-std::unique_ptr<blink::WebMouseEvent> MakeMouseEvent(WebInputEvent::Type type,
-                                                     double timestamp,
-                                                     float x,
-                                                     float y) {
-  std::unique_ptr<blink::WebMouseEvent> mouse_event(new blink::WebMouseEvent);
-  mouse_event->type = type;
-  mouse_event->pointerType = blink::WebPointerProperties::PointerType::Mouse;
-  mouse_event->x = x;
-  mouse_event->y = y;
-  mouse_event->windowX = x;
-  mouse_event->windowY = y;
-  mouse_event->timeStampSeconds = timestamp;
-  mouse_event->clickCount = 1;
-  mouse_event->modifiers = 0;
+ private:
+  std::unique_ptr<VrShellGl> vr_shell_gl_;
+  base::WeakPtr<VrShellGl> weak_vr_shell_gl_;
+
+  // TODO(mthiesse): Remove vr_shell_.
+  VrShell* vr_shell_;
+  base::WeakPtr<VrShell> weak_vr_shell_;
+  base::WeakPtr<VrInputManager> content_input_manager_;
+  base::WeakPtr<VrInputManager> ui_input_manager_;
+  scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
+  gvr_context* gvr_api_;
+};
 
-  return mouse_event;
-}
 }  // namespace
 
 VrShell::VrShell(JNIEnv* env,
@@ -155,17 +96,32 @@ VrShell::VrShell(JNIEnv* env,
                  ui::WindowAndroid* content_window,
                  content::WebContents* ui_contents,
                  ui::WindowAndroid* ui_window,
-                 bool for_web_vr)
+                 bool for_web_vr,
+                 VrShellDelegate* delegate,
+                 gvr_context* gvr_api)
     : WebContentsObserver(ui_contents),
       main_contents_(main_contents),
       ui_contents_(ui_contents),
+      delegate_(delegate),
       metrics_helper_(new VrMetricsHelper(main_contents)),
       main_thread_task_runner_(base::ThreadTaskRunnerHandle::Get()),
       weak_ptr_factory_(this) {
   DCHECK(g_instance == nullptr);
   g_instance = this;
   j_vr_shell_.Reset(env, obj);
-  scene_.reset(new UiScene);
+
+  content_input_manager_.reset(new VrInputManager(main_contents_));
+  ui_input_manager_.reset(new VrInputManager(ui_contents_));
+
+  gl_thread_.reset(new GLThread(this, weak_ptr_factory_.GetWeakPtr(),
+                                content_input_manager_->GetWeakPtr(),
+                                ui_input_manager_->GetWeakPtr(),
+                                main_thread_task_runner_,
+                                gvr_api));
+
+  base::Thread::Options options(base::MessageLoop::TYPE_DEFAULT, 0);
+  options.priority = base::ThreadPriority::DISPLAY;
+  gl_thread_->StartWithOptions(options);
 
   if (for_web_vr)
     metrics_helper_->SetWebVREnabled(true);
@@ -173,36 +129,20 @@ VrShell::VrShell(JNIEnv* env,
       for_web_vr ? UiInterface::Mode::WEB_VR : UiInterface::Mode::STANDARD,
       main_contents_->IsFullscreen()));
   content_compositor_.reset(new VrCompositor(content_window, false));
+  content_compositor_->SetLayer(main_contents_);
   ui_compositor_.reset(new VrCompositor(ui_window, true));
+  ui_compositor_->SetLayer(ui_contents_);
   vr_web_contents_observer_.reset(new VrWebContentsObserver(
       main_contents, html_interface_.get(), this));
 
-  LoadUIContentOnUI();
-
-  gvr::Mat4f identity;
-  SetIdentityM(identity);
-  webvr_head_pose_.resize(kPoseRingBufferSize, identity);
-  webvr_head_pose_valid_.resize(kPoseRingBufferSize, false);
-
-  content_input_manager_.reset(new VrInputManager(main_contents_));
-  ui_input_manager_.reset(new VrInputManager(ui_contents_));
-  weak_content_input_manager_ = content_input_manager_->GetWeakPtr();
-  weak_ui_input_manager_ = ui_input_manager_->GetWeakPtr();
-
-  SetShowingOverscrollGlowOnUI(false);
+  SetShowingOverscrollGlow(false);
 }
 
-void VrShell::UpdateCompositorLayersOnUI(JNIEnv* env,
-                                     const JavaParamRef<jobject>& obj) {
-  content_compositor_->SetLayer(main_contents_);
-  ui_compositor_->SetLayer(ui_contents_);
-}
-
-void VrShell::DestroyOnUI(JNIEnv* env, const JavaParamRef<jobject>& obj) {
+void VrShell::Destroy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   delete this;
 }
 
-void VrShell::LoadUIContentOnUI() {
+void VrShell::LoadUIContent(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   GURL url(kVrShellUIURL);
   ui_contents_->GetController().LoadURL(
       url, content::Referrer(),
@@ -214,757 +154,90 @@ bool RegisterVrShell(JNIEnv* env) {
 }
 
 VrShell::~VrShell() {
-  if (delegate_ && delegate_->GetDeviceProvider()) {
-    delegate_->GetDeviceProvider()->OnGvrDelegateRemoved();
-  }
-  g_instance = nullptr;
-  gl::init::ShutdownGL();
-}
-
-void VrShell::SetDelegateOnUI(JNIEnv* env,
-    const base::android::JavaParamRef<jobject>& obj,
-    const base::android::JavaParamRef<jobject>& delegate) {
-  base::AutoLock lock(gvr_init_lock_);
-  delegate_ = VrShellDelegate::GetNativeDelegate(env, delegate);
-  if (swap_chain_.get()) {
-    delegate_->GetDeviceProvider()->OnGvrDelegateReady(
-        weak_ptr_factory_.GetWeakPtr());
-  }
-}
-
-enum class ViewerType {
-  UNKNOWN_TYPE = 0,
-  CARDBOARD = 1,
-  DAYDREAM = 2,
-  VIEWER_TYPE_MAX,
-};
-
-void VrShell::GvrInitOnGL(JNIEnv* env,
-                      const JavaParamRef<jobject>& obj,
-                      jlong native_gvr_api) {
-  // set the initial webvr state
-  metrics_helper_->SetVRActive(true);
-
-  gvr_api_ =
-      gvr::GvrApi::WrapNonOwned(reinterpret_cast<gvr_context*>(native_gvr_api));
-  // TODO(klausw,crbug.com/655722): should report OnGvrDelegateReady here once
-  // we switch to using a WebVR render surface. We currently need to wait for
-  // the compositor window's size to be known first. See also
-  // ContentSurfaceChanged.
-  controller_.reset(
-      new VrController(reinterpret_cast<gvr_context*>(native_gvr_api)));
-
-
-  ViewerType viewerType;
-  switch (gvr_api_->GetViewerType()) {
-    case gvr::ViewerType::GVR_VIEWER_TYPE_DAYDREAM:
-      viewerType = ViewerType::DAYDREAM;
-      break;
-    case gvr::ViewerType::GVR_VIEWER_TYPE_CARDBOARD:
-      viewerType = ViewerType::CARDBOARD;
-      break;
-    default:
-      NOTREACHED();
-      viewerType = ViewerType::UNKNOWN_TYPE;
-      break;
-  }
-  UMA_HISTOGRAM_ENUMERATION("VRViewerType", static_cast<int>(viewerType),
-      static_cast<int>(ViewerType::VIEWER_TYPE_MAX));
-}
-
-void VrShell::InitializeGlOnGL(JNIEnv* env,
-                           const JavaParamRef<jobject>& obj,
-                           jint content_texture_handle,
-                           jint ui_texture_handle) {
-  base::AutoLock lock(gvr_init_lock_);
-  CHECK(gl::GetGLImplementation() != gl::kGLImplementationNone ||
-        gl::init::InitializeGLOneOff());
-
-  content_texture_id_ = content_texture_handle;
-  ui_texture_id_ = ui_texture_handle;
-
-  // While WebVR is going through the compositor path, it shares
-  // the same texture ID. This will change once it gets its own
-  // surface, but store it separately to avoid future confusion.
-  // TODO(klausw,crbug.com/655722): remove this.
-  webvr_texture_id_ = content_texture_id_;
-  // Out of paranoia, explicitly reset the "pose valid" flags to false
-  // from the GL thread. The constructor ran in the UI thread.
-  // TODO(klausw,crbug.com/655722): remove this.
-  webvr_head_pose_valid_.assign(kPoseRingBufferSize, false);
-
-  gvr_api_->InitializeGl();
-  std::vector<gvr::BufferSpec> specs;
-  // For kFramePrimaryBuffer (primary VrShell and WebVR content)
-  specs.push_back(gvr_api_->CreateBufferSpec());
-  render_size_primary_ = specs[kFramePrimaryBuffer].GetSize();
-  render_size_primary_vrshell_ = render_size_primary_;
-
-  // For kFrameHeadlockedBuffer (for WebVR insecure content warning).
-  // Set this up at fixed resolution, the (smaller) FOV gets set below.
-  specs.push_back(gvr_api_->CreateBufferSpec());
-  specs.back().SetSize(kHeadlockedBufferDimensions);
-  render_size_headlocked_ = specs[kFrameHeadlockedBuffer].GetSize();
-
-  swap_chain_.reset(new gvr::SwapChain(gvr_api_->CreateSwapChain(specs)));
-
-  vr_shell_renderer_.reset(new VrShellRenderer());
-
-  // Allocate a buffer viewport for use in UI drawing. This isn't
-  // initialized at this point, it'll be set from other viewport list
-  // entries as needed.
-  buffer_viewport_.reset(
-      new gvr::BufferViewport(gvr_api_->CreateBufferViewport()));
-
-  // Set up main content viewports. The list has two elements, 0=left
-  // eye and 1=right eye.
-  buffer_viewport_list_.reset(
-      new gvr::BufferViewportList(gvr_api_->CreateEmptyBufferViewportList()));
-  buffer_viewport_list_->SetToRecommendedBufferViewports();
-
-  // Set up head-locked UI viewports, these will be elements 2=left eye
-  // and 3=right eye. For now, use a hardcoded 20-degree-from-center FOV
-  // frustum to reduce rendering cost for this overlay. This fits the
-  // current content, but will need to be adjusted once there's more dynamic
-  // head-locked content that could be larger.
-  headlocked_left_viewport_.reset(
-      new gvr::BufferViewport(gvr_api_->CreateBufferViewport()));
-  buffer_viewport_list_->GetBufferViewport(GVR_LEFT_EYE,
-                                           headlocked_left_viewport_.get());
-  headlocked_left_viewport_->SetSourceBufferIndex(kFrameHeadlockedBuffer);
-  headlocked_left_viewport_->SetReprojection(GVR_REPROJECTION_NONE);
-  headlocked_left_viewport_->SetSourceFov(kHeadlockedBufferFov);
-
-  headlocked_right_viewport_.reset(
-      new gvr::BufferViewport(gvr_api_->CreateBufferViewport()));
-  buffer_viewport_list_->GetBufferViewport(GVR_RIGHT_EYE,
-                                           headlocked_right_viewport_.get());
-  headlocked_right_viewport_->SetSourceBufferIndex(kFrameHeadlockedBuffer);
-  headlocked_right_viewport_->SetReprojection(GVR_REPROJECTION_NONE);
-  headlocked_right_viewport_->SetSourceFov(kHeadlockedBufferFov);
-
-  // Save copies of the first two viewport items for use by WebVR, it
-  // sets its own UV bounds.
-  webvr_left_viewport_.reset(
-      new gvr::BufferViewport(gvr_api_->CreateBufferViewport()));
-  buffer_viewport_list_->GetBufferViewport(GVR_LEFT_EYE,
-                                           webvr_left_viewport_.get());
-  webvr_left_viewport_->SetSourceBufferIndex(kFramePrimaryBuffer);
-
-  webvr_right_viewport_.reset(
-      new gvr::BufferViewport(gvr_api_->CreateBufferViewport()));
-  buffer_viewport_list_->GetBufferViewport(GVR_RIGHT_EYE,
-                                           webvr_right_viewport_.get());
-  webvr_right_viewport_->SetSourceBufferIndex(kFramePrimaryBuffer);
-
-  if (delegate_) {
-    main_thread_task_runner_->PostTask(
-        FROM_HERE, base::Bind(&device::GvrDeviceProvider::OnGvrDelegateReady,
-                              delegate_->GetDeviceProvider(),
-                              weak_ptr_factory_.GetWeakPtr()));
-  }
-}
-
-void VrShell::UpdateControllerOnGL(const gvr::Vec3f& forward_vector) {
-  controller_->UpdateState();
-
-#if defined(ENABLE_VR_SHELL)
-  // Note that button up/down state is transient, so ButtonUpHappened only
-  // returns
-  // true for a single frame (and we're guaranteed not to miss it).
-  if (controller_->ButtonUpHappened(
-          gvr::ControllerButton::GVR_CONTROLLER_BUTTON_APP)) {
-    html_interface_->SetMenuMode(!html_interface_->GetMenuMode());
-
-    // TODO(mthiesse): The page is no longer visible when in menu mode. We
-    // should unfocus or otherwise let it know it's hidden.
-    if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
-      const auto&& task = html_interface_->GetMenuMode() ?
-          &device::GvrDeviceProvider::OnDisplayBlur :
-          &device::GvrDeviceProvider::OnDisplayFocus;
-      main_thread_task_runner_->PostTask(
-          FROM_HERE, base::Bind(task, delegate_->GetDeviceProvider()));
-    }
-  }
-#endif
-  if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
-    // Process screen touch events for Cardboard button compatibility.
-    // Also send tap events for controller "touchpad click" events.
-    if (touch_pending_ ||
-        controller_->ButtonUpHappened(
-            gvr::ControllerButton::GVR_CONTROLLER_BUTTON_CLICK)) {
-      touch_pending_ = false;
-      std::unique_ptr<WebGestureEvent> gesture(new WebGestureEvent());
-      gesture->sourceDevice = blink::WebGestureDeviceTouchpad;
-      gesture->timeStampSeconds =
-          (base::TimeTicks::Now() - base::TimeTicks()).InSecondsF();
-      gesture->type = WebInputEvent::GestureTapDown;
-      gesture->x = 0;
-      gesture->y = 0;
-      SendGestureOnGL(CONTENT, std::move(gesture));
-    }
-
-    return;
-  }
-
-  gvr::Vec3f ergo_neutral_pose;
-  if (!controller_->IsConnected()) {
-    // No controller detected, set up a gaze cursor that tracks the
-    // forward direction.
-    ergo_neutral_pose = {0.0f, 0.0f, -1.0f};
-    controller_quat_ = GetRotationFromZAxis(forward_vector);
-  } else {
-    ergo_neutral_pose = {0.0f, -sin(kErgoAngleOffset), -cos(kErgoAngleOffset)};
-    controller_quat_ = controller_->Orientation();
-  }
-
-  gvr::Mat4f mat = QuatToMatrix(controller_quat_);
-  gvr::Vec3f forward = MatrixVectorMul(mat, ergo_neutral_pose);
-  gvr::Vec3f origin = kHandPosition;
-
-  // If we place the reticle based on elements intersecting the controller beam,
-  // we can end up with the reticle hiding behind elements, or jumping laterally
-  // in the field of view. This is physically correct, but hard to use. For
-  // usability, do the following instead:
-  //
-  // - Project the controller laser onto an outer surface, which is the
-  //   closer of the desktop plane, or a distance-limiting sphere.
-  // - Create a vector between the eyes and the outer surface point.
-  // - If any UI elements intersect this vector, choose the closest to the eyes,
-  //   and place the reticle at the intersection point.
-
-  // Find distance to a corner of the content quad, and limit the cursor
-  // distance to a multiple of that distance. This lets us keep the reticle on
-  // the content plane near the content window, and on the surface of a sphere
-  // in other directions. Note that this approach uses distance from controller,
-  // rather than eye, for simplicity. This will make the sphere slightly
-  // off-center.
-  float distance = kDefaultReticleDistance;
-  ContentRectangle* content_plane = scene_->GetContentQuad();
-  if (content_plane) {
-    distance = content_plane->GetRayDistance(origin, forward);
-    gvr::Vec3f corner = {0.5f, 0.5f, 0.0f};
-    corner = MatrixVectorMul(content_plane->transform.to_world, corner);
-    float max_distance = Distance(origin, corner) * kReticleDistanceMultiplier;
-    if (distance > max_distance || distance <= 0.0f) {
-      distance = max_distance;
-    }
-  }
-
-  target_point_ = GetRayPoint(origin, forward, distance);
-  gvr::Vec3f eye_to_target = target_point_;
-  NormalizeVector(eye_to_target);
-
-  // Determine which UI element (if any) intersects the line between the eyes
-  // and the controller target position.
-  float closest_element_distance = std::numeric_limits<float>::infinity();
-  int pixel_x = 0;
-  int pixel_y = 0;
-  target_element_ = nullptr;
-  InputTarget input_target = NONE;
-
-  for (const auto& plane : scene_->GetUiElements()) {
-    if (!plane->visible || !plane->hit_testable) {
-      continue;
-    }
-    float distance_to_plane = plane->GetRayDistance(kOrigin, eye_to_target);
-    gvr::Vec3f plane_intersection_point =
-        GetRayPoint(kOrigin, eye_to_target, distance_to_plane);
-
-    gvr::Vec3f rect_2d_point =
-        MatrixVectorMul(plane->transform.from_world, plane_intersection_point);
-    if (distance_to_plane > 0 && distance_to_plane < closest_element_distance) {
-      float x = rect_2d_point.x + 0.5f;
-      float y = 0.5f - rect_2d_point.y;
-      bool is_inside = x >= 0.0f && x < 1.0f && y >= 0.0f && y < 1.0f;
-      if (!is_inside)
-        continue;
-
-      closest_element_distance = distance_to_plane;
-      Rectf pixel_rect;
-      if (plane->content_quad) {
-        pixel_rect = {0, 0, content_tex_css_width_, content_tex_css_height_};
-      } else {
-        pixel_rect = {plane->copy_rect.x, plane->copy_rect.y,
-                      plane->copy_rect.width, plane->copy_rect.height};
-      }
-      pixel_x = pixel_rect.width * x + pixel_rect.x;
-      pixel_y = pixel_rect.height * y + pixel_rect.y;
-
-      target_point_ = plane_intersection_point;
-      target_element_ = plane.get();
-      input_target = plane->content_quad ? CONTENT : UI;
-    }
-  }
-  SendEventsToTargetOnGL(input_target, pixel_x, pixel_y);
-}
-
-void VrShell::SendEventsToTargetOnGL(InputTarget input_target,
-                                 int pixel_x,
-                                 int pixel_y) {
-  std::vector<std::unique_ptr<WebGestureEvent>> gesture_list =
-      controller_->DetectGestures();
-  double timestamp = gesture_list.front()->timeStampSeconds;
-
-  if (touch_pending_) {
-    touch_pending_ = false;
-    std::unique_ptr<WebGestureEvent> event(new WebGestureEvent());
-    event->type = WebInputEvent::GestureTapDown;
-    event->sourceDevice = blink::WebGestureDeviceTouchpad;
-    event->timeStampSeconds = timestamp;
-    event->x = pixel_x;
-    event->y = pixel_y;
-    gesture_list.push_back(std::move(event));
-  }
-
-  for (const auto& gesture : gesture_list) {
-    switch (gesture->type) {
-      case WebInputEvent::GestureScrollBegin:
-      case WebInputEvent::GestureScrollUpdate:
-      case WebInputEvent::GestureScrollEnd:
-      case WebInputEvent::GestureFlingCancel:
-      case WebInputEvent::GestureFlingStart:
-        SendGestureOnGL(CONTENT,
-                        base::WrapUnique(new WebGestureEvent(*gesture)));
-        break;
-      case WebInputEvent::GestureTapDown:
-        gesture->x = pixel_x;
-        gesture->y = pixel_y;
-        if (input_target != NONE)
-          SendGestureOnGL(input_target,
-                          base::WrapUnique(new WebGestureEvent(*gesture)));
-        break;
-      case WebInputEvent::Undefined:
-        break;
-      default:
-        NOTREACHED();
-    }
-  }
-
-  // Hover support
-  bool new_target = input_target != current_input_target_;
-  if (new_target && current_input_target_ != NONE) {
-    // Send a move event indicating that the pointer moved off of an element.
-    SendGestureOnGL(current_input_target_,
-                    MakeMouseEvent(WebInputEvent::MouseLeave, timestamp, 0, 0));
-  }
-
-  current_input_target_ = input_target;
-  if (current_input_target_ != NONE) {
-    WebInputEvent::Type type =
-        new_target ? WebInputEvent::MouseEnter : WebInputEvent::MouseMove;
-    SendGestureOnGL(input_target,
-                    MakeMouseEvent(type, timestamp, pixel_x, pixel_y));
-  }
-}
-
-void VrShell::SendGestureOnGL(InputTarget input_target,
-                          std::unique_ptr<blink::WebInputEvent> event) {
-  DCHECK(input_target != NONE);
-  const base::WeakPtr<VrInputManager>& weak_ptr =
-      input_target == CONTENT ? weak_content_input_manager_
-                              : weak_ui_input_manager_;
-  main_thread_task_runner_->PostTask(
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  thread->task_runner()->PostTask(
       FROM_HERE,
-      base::Bind(&VrInputManager::ProcessUpdatedGesture, weak_ptr,
-                 base::Passed(std::move(event))));
+      base::Bind(&GLThread::StopRenderLoop, base::Unretained(thread)));
+  {
+    // Unfortunately stopping threads asserts that IO is allowed, and on the
+    // Android UI thread, IO is not allowed by default. However, we can't allow
+    // the thread to keep running, because the GVR instance is about to be
+    // deleted and we'll segfault if the thread keeps running for any amount of
+    // time.
+    // Our options are:

[brettw, 2016/12/12 19:12:40]

Can you replace this "options" section with the information about object
ownership and lifetimes you put in the review comments?

[mthiesse, 2016/12/12 19:49:30]

Done.

+    // 1. Use the *heavily* discouraged ScopedAllowIO.
+    // 2. a. Post a task to the GLThread telling it to stop delete vr_shell_gl.
+    //    b. Wait for a signal that this has been completed.
+    //    c. Call thread->StopSoon().
+    //    d. Post a task to the current thread to check if GLThread has stopped
+    //       yet.
+    //    e. If the thread has stopped, delete it, otherwise post delayed to
+    //       the current thread all over again. Repeat as needed.
+    //
+    // TODO(mthiesse): I've gone with option 1. Are there better options?
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
+    thread->Stop();
+  }
+  delegate_->RemoveDelegate();
+  g_instance = nullptr;
 }
 
 void VrShell::SetGvrPoseForWebVr(const gvr::Mat4f& pose, uint32_t pose_num) {
-  webvr_head_pose_[pose_num % kPoseRingBufferSize] = pose;
-  webvr_head_pose_valid_[pose_num % kPoseRingBufferSize] = true;
-}
-
-int GetPixelEncodedPoseIndexByte() {
-  TRACE_EVENT0("gpu", "VrShell::GetPixelEncodedPoseIndex");
-  // Read the pose index encoded in a bottom left pixel as color values.
-  // See also third_party/WebKit/Source/modules/vr/VRDisplay.cpp which
-  // encodes the pose index, and device/vr/android/gvr/gvr_device.cc
-  // which tracks poses. Returns the low byte (0..255) if valid, or -1
-  // if not valid due to bad magic number.
-  uint8_t pixels[4];
-  // Assume we're reading from the framebuffer we just wrote to.
-  // That's true currently, we may need to use glReadBuffer(GL_BACK)
-  // or equivalent if the rendering setup changes in the future.
-  glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
-
-  // Check for the magic number written by VRDevice.cpp on submit.
-  // This helps avoid glitches from garbage data in the render
-  // buffer that can appear during initialization or resizing. These
-  // often appear as flashes of all-black or all-white pixels.
-  if (pixels[1] == kWebVrPosePixelMagicNumbers[0] &&
-      pixels[2] == kWebVrPosePixelMagicNumbers[1]) {
-    // Pose is good.
-    return pixels[0];
-  }
-  VLOG(1) << "WebVR: reject decoded pose index " << (int)pixels[0] <<
-      ", bad magic number " << (int)pixels[1] << ", " << (int)pixels[2];
-  return -1;
-}
-
-bool VrShell::WebVrPoseByteIsValidOnGL(int pose_index_byte) {
-  if (pose_index_byte < 0) {
-    return false;
-  }
-  if (!webvr_head_pose_valid_[pose_index_byte % kPoseRingBufferSize]) {
-    VLOG(1) << "WebVR: reject decoded pose index " << pose_index_byte <<
-        ", not a valid pose";
-    return false;
-  }
-  return true;
-}
-
-void VrShell::DrawFrameOnGL(JNIEnv* env, const JavaParamRef<jobject>& obj) {
-  TRACE_EVENT0("gpu", "VrShell::DrawFrame");
-  // Reset the viewport list to just the pair of viewports for the
-  // primary buffer each frame. Head-locked viewports get added by
-  // DrawVrShell if needed.
-  buffer_viewport_list_->SetToRecommendedBufferViewports();
-
-  if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
-    // If needed, resize the primary buffer for use with WebVR.
-    if (render_size_primary_ != render_size_primary_webvr_) {
-      if (!render_size_primary_webvr_.width) {
-        VLOG(2) << "WebVR rendering size not known yet, dropping frame";
-        return;
-      }
-      render_size_primary_ = render_size_primary_webvr_;
-      swap_chain_->ResizeBuffer(kFramePrimaryBuffer, render_size_primary_);
-    }
-  } else {
-    if (render_size_primary_ != render_size_primary_vrshell_) {
-      render_size_primary_ = render_size_primary_vrshell_;
-      swap_chain_->ResizeBuffer(kFramePrimaryBuffer, render_size_primary_);
-    }
-  }
-
-  gvr::Frame frame = swap_chain_->AcquireFrame();
-  gvr::ClockTimePoint target_time = gvr::GvrApi::GetTimePointNow();
-  target_time.monotonic_system_time_nanos += kPredictionTimeWithoutVsyncNanos;
-
-  gvr::Mat4f head_pose =
-      gvr_api_->GetHeadSpaceFromStartSpaceRotation(target_time);
-
-  gvr::Vec3f position = GetTranslation(head_pose);
-  if (position.x == 0.0f && position.y == 0.0f && position.z == 0.0f) {
-    // This appears to be a 3DOF pose without a neck model. Add one.
-    // The head pose has redundant data. Assume we're only using the
-    // object_from_reference_matrix, we're not updating position_external.
-    // TODO: Not sure what object_from_reference_matrix is. The new api removed
-    // it. For now, removing it seems working fine.
-    gvr_api_->ApplyNeckModel(head_pose, 1.0f);
-  }
-
-  // Bind the primary framebuffer.
-  frame.BindBuffer(kFramePrimaryBuffer);
-
-  HandleQueuedTasksOnGL();
-
-  // Update the render position of all UI elements (including desktop).
-  const float screen_tilt = kDesktopScreenTiltDefault * M_PI / 180.0f;
-  scene_->UpdateTransforms(screen_tilt, UiScene::TimeInMicroseconds());
-
-  UpdateControllerOnGL(GetForwardVector(head_pose));
-
-  if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
-    DrawWebVrOnGL();
-
-    // When using async reprojection, we need to know which pose was used in
-    // the WebVR app for drawing this frame. Due to unknown amounts of
-    // buffering in the compositor and SurfaceTexture, we read the pose number
-    // from a corner pixel. There's no point in doing this for legacy
-    // distortion rendering since that doesn't need a pose, and reading back
-    // pixels is an expensive operation. TODO(klausw,crbug.com/655722): stop
-    // doing this once we have working no-compositor rendering for WebVR.
-    if (gvr_api_->GetAsyncReprojectionEnabled()) {
-      int pose_index_byte = GetPixelEncodedPoseIndexByte();
-      if (WebVrPoseByteIsValidOnGL(pose_index_byte)) {
-        // We have a valid pose, use it for reprojection.
-        webvr_left_viewport_->SetReprojection(GVR_REPROJECTION_FULL);
-        webvr_right_viewport_->SetReprojection(GVR_REPROJECTION_FULL);
-        head_pose = webvr_head_pose_[pose_index_byte % kPoseRingBufferSize];
-        // We can't mark the used pose as invalid since unfortunately
-        // we have to reuse them. The compositor will re-submit stale
-        // frames on vsync, and we can't tell that this has happened
-        // until we've read the pose index from it, and at that point
-        // it's too late to skip rendering.
-      } else {
-        // If we don't get a valid frame ID back we shouldn't attempt
-        // to reproject by an invalid matrix, so turn off reprojection
-        // instead. Invalid poses can permanently break reprojection
-        // for this GVR instance: http://crbug.com/667327
-        webvr_left_viewport_->SetReprojection(GVR_REPROJECTION_NONE);
-        webvr_right_viewport_->SetReprojection(GVR_REPROJECTION_NONE);
-      }
-    }
-  }
-
-  DrawVrShellOnGL(head_pose, frame);
-
-  frame.Unbind();
-  frame.Submit(*buffer_viewport_list_, head_pose);
-}
-
-void VrShell::DrawVrShellOnGL(const gvr::Mat4f& head_pose,
-                          gvr::Frame &frame) {
-  TRACE_EVENT0("gpu", "VrShell::DrawVrShell");
-  std::vector<const ContentRectangle*> head_locked_elements;
-  std::vector<const ContentRectangle*> world_elements;
-  for (const auto& rect : scene_->GetUiElements()) {
-    if (!rect->visible) {
-      continue;
-    }
-    if (rect->lock_to_fov) {
-      head_locked_elements.push_back(rect.get());
-    } else {
-      world_elements.push_back(rect.get());
-    }
-  }
-
-  if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
-    // WebVR is incompatible with 3D world compositing since the
-    // depth buffer was already populated with unknown scaling - the
-    // WebVR app has full control over zNear/zFar. Just leave the
-    // existing content in place in the primary buffer without
-    // clearing. Currently, there aren't any world elements in WebVR
-    // mode, this will need further testing if those get added
-    // later.
-  } else {
-    // Non-WebVR mode, enable depth testing and clear the primary buffers.
-    glEnable(GL_CULL_FACE);
-    glEnable(GL_DEPTH_TEST);
-    glDepthMask(GL_TRUE);
-
-    glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
-    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-  }
-
-  if (!world_elements.empty()) {
-    DrawUiViewOnGL(&head_pose, world_elements, render_size_primary_,
-               kViewportListPrimaryOffset);
-  }
-
-  if (!head_locked_elements.empty()) {
-    // Add head-locked viewports. The list gets reset to just
-    // the recommended viewports (for the primary buffer) each frame.
-    buffer_viewport_list_->SetBufferViewport(
-        kViewportListHeadlockedOffset + GVR_LEFT_EYE,
-        *headlocked_left_viewport_);
-    buffer_viewport_list_->SetBufferViewport(
-        kViewportListHeadlockedOffset + GVR_RIGHT_EYE,
-        *headlocked_right_viewport_);
-
-    // Bind the headlocked framebuffer.
-    frame.BindBuffer(kFrameHeadlockedBuffer);
-    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
-    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-    DrawUiViewOnGL(nullptr, head_locked_elements, render_size_headlocked_,
-               kViewportListHeadlockedOffset);
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  if (thread->GetVrShellGlUnsafe()) {

[bshe, 2016/12/12 20:30:20]

why do you use Unsafe here instead of post to GL thread? Perhaps add comment
about why?

+    thread->GetVrShellGlUnsafe()->SetGvrPoseForWebVr(pose, pose_num);
   }
 }
 
 void VrShell::SetWebVRRenderSurfaceSize(int width, int height) {
-  render_size_primary_webvr_.width = width;
-  render_size_primary_webvr_.height = height;
-  // TODO(klausw,crbug.com/655722): set the WebVR render surface size here once
-  // we have that.
-}
-
-gvr::Sizei VrShell::GetWebVRCompositorSurfaceSize() {
-  // This is a stopgap while we're using the WebVR compositor rendering path.
-  // TODO(klausw,crbug.com/655722): Remove this method and member once we're
-  // using a separate WebVR render surface.
-  return content_tex_physical_size_;
-}
-
-
-void VrShell::DrawUiViewOnGL(const gvr::Mat4f* head_pose,
-                         const std::vector<const ContentRectangle*>& elements,
-                         const gvr::Sizei& render_size, int viewport_offset) {
-  TRACE_EVENT0("gpu", "VrShell::DrawUiView");
-  for (auto eye : {GVR_LEFT_EYE, GVR_RIGHT_EYE}) {
-    buffer_viewport_list_->GetBufferViewport(
-        eye + viewport_offset, buffer_viewport_.get());
-
-    gvr::Mat4f view_matrix = gvr_api_->GetEyeFromHeadMatrix(eye);
-    if (head_pose != nullptr) {
-      view_matrix = MatrixMul(view_matrix, *head_pose);
-    }
-
-    gvr::Recti pixel_rect =
-        CalculatePixelSpaceRect(render_size, buffer_viewport_->GetSourceUv());
-    glViewport(pixel_rect.left, pixel_rect.bottom,
-               pixel_rect.right - pixel_rect.left,
-               pixel_rect.top - pixel_rect.bottom);
-
-    const gvr::Mat4f render_matrix = MatrixMul(
-        PerspectiveMatrixFromView(
-            buffer_viewport_->GetSourceFov(), kZNear, kZFar),
-        view_matrix);
-
-    DrawElementsOnGL(render_matrix, elements);
-    if (head_pose != nullptr &&
-        html_interface_->GetMode() != UiInterface::Mode::WEB_VR) {
-      DrawCursorOnGL(render_matrix);
-    }
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  if (thread->GetVrShellGlUnsafe()) {
+    thread->GetVrShellGlUnsafe()->SetWebVRRenderSurfaceSize(width, height);
   }
 }
 
-void VrShell::DrawElementsOnGL(
-    const gvr::Mat4f& render_matrix,
-    const std::vector<const ContentRectangle*>& elements) {
-  for (const auto& rect : elements) {
-    Rectf copy_rect;
-    jint texture_handle;
-    if (rect->content_quad) {
-      copy_rect = {0, 0, 1, 1};
-      texture_handle = content_texture_id_;
-    } else {
-      copy_rect.x = static_cast<float>(rect->copy_rect.x) / ui_tex_css_width_;
-      copy_rect.y = static_cast<float>(rect->copy_rect.y) / ui_tex_css_height_;
-      copy_rect.width = static_cast<float>(rect->copy_rect.width) /
-          ui_tex_css_width_;
-      copy_rect.height = static_cast<float>(rect->copy_rect.height) /
-          ui_tex_css_height_;
-      texture_handle = ui_texture_id_;
-    }
-    gvr::Mat4f transform = MatrixMul(render_matrix, rect->transform.to_world);
-    vr_shell_renderer_->GetTexturedQuadRenderer()->Draw(
-        texture_handle, transform, copy_rect);
-  }
-}
-
-void VrShell::DrawCursorOnGL(const gvr::Mat4f& render_matrix) {
-  gvr::Mat4f mat;
-  SetIdentityM(mat);
-
-  // Draw the reticle.
-
-  // Scale the pointer to have a fixed FOV size at any distance.
-  const float eye_to_target = Distance(target_point_, kOrigin);
-  ScaleM(mat, mat, kReticleWidth * eye_to_target,
-         kReticleHeight * eye_to_target, 1.0f);
-
-  gvr::Quatf rotation;
-  if (target_element_ != nullptr) {
-    // Make the reticle planar to the element it's hitting.
-    rotation = GetRotationFromZAxis(target_element_->GetNormal());
-  } else {
-    // Rotate the cursor to directly face the eyes.
-    rotation = GetRotationFromZAxis(target_point_);
-  }
-  mat = MatrixMul(QuatToMatrix(rotation), mat);
-
-  // Place the pointer slightly in front of the plane intersection point.
-  TranslateM(mat, mat, target_point_.x * kReticleOffset,
-             target_point_.y * kReticleOffset,
-             target_point_.z * kReticleOffset);
-
-  gvr::Mat4f transform = MatrixMul(render_matrix, mat);
-  vr_shell_renderer_->GetReticleRenderer()->Draw(transform);
-
-  // Draw the laser.
-
-  // Find the length of the beam (from hand to target).
-  const float laser_length = Distance(kHandPosition, target_point_);
-
-  // Build a beam, originating from the origin.
-  SetIdentityM(mat);
-
-  // Move the beam half its height so that its end sits on the origin.
-  TranslateM(mat, mat, 0.0f, 0.5f, 0.0f);
-  ScaleM(mat, mat, kLaserWidth, laser_length, 1);
-
-  // Tip back 90 degrees to flat, pointing at the scene.
-  const gvr::Quatf q = QuatFromAxisAngle({1.0f, 0.0f, 0.0f}, -M_PI / 2);
-  mat = MatrixMul(QuatToMatrix(q), mat);
-
-  const gvr::Vec3f beam_direction = {
-    target_point_.x - kHandPosition.x,
-    target_point_.y - kHandPosition.y,
-    target_point_.z - kHandPosition.z
-  };
-  const gvr::Mat4f beam_direction_mat =
-      QuatToMatrix(GetRotationFromZAxis(beam_direction));
-
-  // Render multiple faces to make the laser appear cylindrical.
-  const int faces = 4;
-  for (int i = 0; i < faces; i++) {
-    // Rotate around Z.
-    const float angle = M_PI * 2 * i / faces;
-    const gvr::Quatf rot = QuatFromAxisAngle({0.0f, 0.0f, 1.0f}, angle);
-    gvr::Mat4f face_transform = MatrixMul(QuatToMatrix(rot), mat);
-
-    // Orient according to target direction.
-    face_transform = MatrixMul(beam_direction_mat, face_transform);
-
-    // Move the beam origin to the hand.
-    TranslateM(face_transform, face_transform, kHandPosition.x, kHandPosition.y,
-               kHandPosition.z);
-
-    transform = MatrixMul(render_matrix, face_transform);
-    vr_shell_renderer_->GetLaserRenderer()->Draw(transform);
+gvr::Sizei VrShell::GetWebVRCompositorSurfaceSize() {
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  if (thread->GetVrShellGlUnsafe()) {
+    return thread->GetVrShellGlUnsafe()->GetWebVRCompositorSurfaceSize();
   }
+  return gvr::Sizei();
 }
 
-void VrShell::DrawWebVrOnGL() {
-  TRACE_EVENT0("gpu", "VrShell::DrawWebVr");
-  // Don't need face culling, depth testing, blending, etc. Turn it all off.
-  glDisable(GL_CULL_FACE);
-  glDepthMask(GL_FALSE);
-  glDisable(GL_DEPTH_TEST);
-  glDisable(GL_SCISSOR_TEST);
-  glDisable(GL_BLEND);
-  glDisable(GL_POLYGON_OFFSET_FILL);
-
-  glViewport(0, 0, render_size_primary_.width, render_size_primary_.height);
-  vr_shell_renderer_->GetWebVrRenderer()->Draw(webvr_texture_id_);
-
-  buffer_viewport_list_->SetBufferViewport(GVR_LEFT_EYE,
-                                           *webvr_left_viewport_);
-  buffer_viewport_list_->SetBufferViewport(GVR_RIGHT_EYE,
-                                           *webvr_right_viewport_);
+void VrShell::OnTriggerEvent(JNIEnv* env,
+                             const JavaParamRef<jobject>& obj) {
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  thread->task_runner()->PostTask(FROM_HERE,
+                                  base::Bind(&VrShellGl::OnTriggerEvent,
+                                             thread->GetVrShellGl()));
 }
 
-void VrShell::OnTriggerEventOnUI(JNIEnv* env,
-                                 const JavaParamRef<jobject>& obj) {
-  // Set a flag to handle this on the render thread at the next frame.
-  touch_pending_ = true;
-}
-
-void VrShell::OnPauseOnUI(JNIEnv* env, const JavaParamRef<jobject>& obj) {
-  if (gvr_api_ == nullptr)
-    return;
-
-  // TODO(mthiesse): Clean up threading here.
-  controller_->OnPause();
-  gvr_api_->PauseTracking();
-  SetShowingOverscrollGlowOnUI(true);
+void VrShell::OnPause(JNIEnv* env, const JavaParamRef<jobject>& obj) {
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  thread->task_runner()->PostTask(
+      FROM_HERE, base::Bind(&VrShellGl::OnPause, thread->GetVrShellGl()));
 
   // exit vr session
   metrics_helper_->SetVRActive(false);
+  SetShowingOverscrollGlow(true);
 }
 
-void VrShell::OnResumeOnUI(JNIEnv* env, const JavaParamRef<jobject>& obj) {
-  if (gvr_api_ == nullptr)
-    return;
-
-  // TODO(mthiesse): Clean up threading here.
-  gvr_api_->RefreshViewerProfile();
-  gvr_api_->ResumeTracking();
-  controller_->OnResume();
-  SetShowingOverscrollGlowOnUI(false);
+void VrShell::OnResume(JNIEnv* env, const JavaParamRef<jobject>& obj) {
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  thread->task_runner()->PostTask(
+      FROM_HERE, base::Bind(&VrShellGl::OnResume, thread->GetVrShellGl()));
 
   // exit vr session
   metrics_helper_->SetVRActive(true);
+  SetShowingOverscrollGlow(false);
 }
 
-void VrShell::SetShowingOverscrollGlowOnUI(bool showing_glow) {
+void VrShell::SetShowingOverscrollGlow(bool showing_glow) {
   main_contents_->GetRenderWidgetHostView()->SetShowingOverscrollGlow(
       showing_glow);
 }
 
-base::WeakPtr<VrShell> VrShell::GetWeakPtrOnUI(
+base::WeakPtr<VrShell> VrShell::GetWeakPtr(
     const content::WebContents* web_contents) {
   // Ensure that the WebContents requesting the VrShell instance is the one
   // we created.
@@ -973,13 +246,13 @@ base::WeakPtr<VrShell> VrShell::GetWeakPtrOnUI(
   return base::WeakPtr<VrShell>(nullptr);
 }
 
-void VrShell::OnDomContentsLoadedOnUI() {
+void VrShell::OnDomContentsLoaded() {
   html_interface_->SetURL(main_contents_->GetVisibleURL());
   html_interface_->SetLoading(main_contents_->IsLoading());
   html_interface_->OnDomContentsLoaded();
 }
 
-void VrShell::SetWebVrModeOnUI(JNIEnv* env,
+void VrShell::SetWebVrMode(JNIEnv* env,
                            const base::android::JavaParamRef<jobject>& obj,
                            bool enabled) {
   metrics_helper_->SetWebVREnabled(enabled);
@@ -999,73 +272,82 @@ void VrShell::SubmitWebVRFrame() {}
 
 void VrShell::UpdateWebVRTextureBounds(const gvr::Rectf& left_bounds,
                                        const gvr::Rectf& right_bounds) {
-  webvr_left_viewport_->SetSourceUv(left_bounds);
-  webvr_right_viewport_->SetSourceUv(right_bounds);
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  if (thread->GetVrShellGlUnsafe()) {
+    thread->GetVrShellGlUnsafe()->UpdateWebVRTextureBounds(left_bounds,
+                                                           right_bounds);
+  }
 }
 
+// TODO(mthiesse): Do not expose GVR API outside of GL thread.
+// It's not thread-safe.
 gvr::GvrApi* VrShell::gvr_api() {
-  return gvr_api_.get();
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  if (thread->GetVrShellGlUnsafe()) {
+    return thread->GetVrShellGlUnsafe()->gvr_api();
+  }
+  CHECK(false);
+  return nullptr;
 }
 
-void VrShell::SurfacesChangedOnUI(JNIEnv* env,
-                              const JavaParamRef<jobject>& object,
-                              const JavaParamRef<jobject>& content_surface,
-                              const JavaParamRef<jobject>& ui_surface) {
+void VrShell::SurfacesChanged(jobject content_surface, jobject ui_surface) {
   content_compositor_->SurfaceChanged(content_surface);
   ui_compositor_->SurfaceChanged(ui_surface);
 }
 
-void VrShell::ContentBoundsChangedOnUI(JNIEnv* env,
+void VrShell::GvrDelegateReady() {
+  delegate_->SetDelegate(weak_ptr_factory_.GetWeakPtr());
+}
+
+void VrShell::ContentBoundsChanged(JNIEnv* env,
                                    const JavaParamRef<jobject>& object,
                                    jint width, jint height, jfloat dpr) {
   TRACE_EVENT0("gpu", "VrShell::ContentBoundsChanged");
-  content_tex_physical_size_.width = width;
-  content_tex_physical_size_.height = height;
-  // TODO(mthiesse): Synchronize with GL thread, and update tex css size in
-  // response to MainFrameWasResized, not here.
-  content_tex_css_width_ = width / dpr;
-  content_tex_css_height_ = height / dpr;
-
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  // TODO(mthiesse): Remove this blocking wait. Queue up events if thread isn't
+  // finished starting?
+  thread->WaitUntilThreadStarted();
+  CHECK(thread->task_runner()->PostTask(
+      FROM_HERE, base::Bind(&VrShellGl::ContentPhysicalBoundsChanged,
+                            thread->GetVrShellGl(),
+                            width, height)));
   content_compositor_->SetWindowBounds(width, height);
 }
 
-void VrShell::UIBoundsChangedOnUI(JNIEnv* env,
+void VrShell::UIBoundsChanged(JNIEnv* env,
                               const JavaParamRef<jobject>& object,
                               jint width, jint height, jfloat dpr) {
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  // TODO(mthiesse): Remove this blocking wait. Queue up events if thread isn't
+  // finished starting?
+  thread->WaitUntilThreadStarted();
+  thread->task_runner()->PostTask(
+      FROM_HERE, base::Bind(&VrShellGl::UIPhysicalBoundsChanged,
+                            thread->GetVrShellGl(),
+                            width, height));
   ui_compositor_->SetWindowBounds(width, height);
 }
 
-UiScene* VrShell::GetSceneOnGL() {
-  return scene_.get();
+UiScene* VrShell::GetScene() {
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  // TODO(mthiesse): Remove this blocking wait. Queue up events if thread isn't
+  // finished starting?
+  thread->WaitUntilThreadStarted();
+  if (thread->GetVrShellGlUnsafe()) {
+    return thread->GetVrShellGlUnsafe()->GetScene();
+  }
+  return nullptr;
 }
 
-UiInterface* VrShell::GetUiInterfaceOnGL() {
+UiInterface* VrShell::GetUiInterface() {
   return html_interface_.get();
 }
 
-void VrShell::QueueTaskOnUI(base::Callback<void()>& callback) {
-  base::AutoLock lock(task_queue_lock_);
-  task_queue_.push(callback);
+void VrShell::QueueTask(base::Callback<void()>& callback) {
+  gl_thread_->task_runner()->PostTask(FROM_HERE, callback);
 }
 
-void VrShell::HandleQueuedTasksOnGL() {
-  // To protect a stream of tasks from blocking rendering indefinitely,
-  // process only the number of tasks present when first checked.
-  std::vector<base::Callback<void()>> tasks;
-  {
-    base::AutoLock lock(task_queue_lock_);
-    const size_t count = task_queue_.size();
-    for (size_t i = 0; i < count; i++) {
-      tasks.push_back(task_queue_.front());
-      task_queue_.pop();
-    }
-  }
-  for (auto &task : tasks) {
-    task.Run();
-  }
-}
-
-void VrShell::DoUiActionOnUI(const UiAction action) {
+void VrShell::DoUiAction(const UiAction action) {
   content::NavigationController& controller = main_contents_->GetController();
   switch (action) {
     case HISTORY_BACK:
@@ -1106,60 +388,83 @@ void VrShell::RenderViewHostChanged(content::RenderViewHost* old_host,
 void VrShell::MainFrameWasResized(bool width_changed) {
   display::Display display = display::Screen::GetScreen()
       ->GetDisplayNearestWindow(ui_contents_->GetNativeView());
-  // TODO(mthiesse): Synchronize with GL thread.
-  ui_tex_css_width_ = display.size().width();
-  ui_tex_css_height_ = display.size().height();
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  // TODO(mthiesse): Remove this blocking wait. Queue up events if thread isn't
+  // finished starting?
+  thread->WaitUntilThreadStarted();
+  thread->task_runner()->PostTask(
+      FROM_HERE, base::Bind(&VrShellGl::UIBoundsChanged,
+                            thread->GetVrShellGl(),
+                            display.size().width(), display.size().height()));
+}
+
+void VrShell::ContentFrameWasResized(bool width_changed) {
+  display::Display display = display::Screen::GetScreen()
+      ->GetDisplayNearestWindow(main_contents_->GetNativeView());
+  GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
+  // TODO(mthiesse): Remove this blocking wait. Queue up events if thread isn't
+  // finished starting?
+  thread->WaitUntilThreadStarted();
+  thread->task_runner()->PostTask(
+      FROM_HERE, base::Bind(&VrShellGl::ContentBoundsChanged,
+                            thread->GetVrShellGl(),
+                            display.size().width(), display.size().height()));
 }
 
 void VrShell::WebContentsDestroyed() {
   ui_input_manager_.reset();
   ui_contents_ = nullptr;
   // TODO(mthiesse): Handle web contents being destroyed.
-  delegate_->ForceExitVr();
+  ForceExitVR();
 }
 
-void VrShell::ContentWebContentsDestroyedOnUI() {
+void VrShell::ContentWebContentsDestroyed() {
   content_input_manager_.reset();
   main_contents_ = nullptr;
   // TODO(mthiesse): Handle web contents being destroyed.
-  delegate_->ForceExitVr();
+  ForceExitVR();
 }
 
-void VrShell::ContentWasHiddenOnUI() {
+void VrShell::ContentWasHidden() {
   // Ensure we don't continue sending input to it.
   content_input_manager_.reset();
   // TODO(mthiesse): Handle web contents being hidden.
+  ForceExitVR();
+}
+
+void VrShell::ForceExitVR() {

[bshe, 2016/12/12 20:30:20]

nit: VR/Vr to be consistent

   delegate_->ForceExitVr();
 }
 
-void VrShell::SetContentCssSizeOnUI(float width, float height, float dpr) {
+void VrShell::SetContentCssSize(float width, float height, float dpr) {
   JNIEnv* env = base::android::AttachCurrentThread();
-  Java_VrShellImpl_setContentCssSizeOnUI(env, j_vr_shell_.obj(), width, height,
-                                         dpr);
+  Java_VrShellImpl_setContentCssSize(env, j_vr_shell_.obj(), width, height,
+                                     dpr);
 }
 
-void VrShell::SetUiCssSizeOnUI(float width, float height, float dpr) {
+void VrShell::SetUiCssSize(float width, float height, float dpr) {
   JNIEnv* env = base::android::AttachCurrentThread();
-  Java_VrShellImpl_setUiCssSizeOnUI(env, j_vr_shell_.obj(), width, height, dpr);
+  Java_VrShellImpl_setUiCssSize(env, j_vr_shell_.obj(), width, height, dpr);
 }
 
 // ----------------------------------------------------------------------------
 // Native JNI methods
 // ----------------------------------------------------------------------------
 
-jlong InitOnUI(JNIEnv* env,
-               const JavaParamRef<jobject>& obj,
-               const JavaParamRef<jobject>& content_web_contents,
-               jlong content_window_android,
-               const JavaParamRef<jobject>& ui_web_contents,
-               jlong ui_window_android,
-               jboolean for_web_vr) {
+jlong Init(JNIEnv* env, const JavaParamRef<jobject>& obj,
+           const JavaParamRef<jobject>& content_web_contents,
+           jlong content_window_android,
+           const JavaParamRef<jobject>& ui_web_contents,
+           jlong ui_window_android, jboolean for_web_vr,
+           const base::android::JavaParamRef<jobject>& delegate,
+           jlong gvr_api) {
   return reinterpret_cast<intptr_t>(new VrShell(
       env, obj, content::WebContents::FromJavaWebContents(content_web_contents),
       reinterpret_cast<ui::WindowAndroid*>(content_window_android),
       content::WebContents::FromJavaWebContents(ui_web_contents),
       reinterpret_cast<ui::WindowAndroid*>(ui_window_android),
-      for_web_vr));
+      for_web_vr, VrShellDelegate::GetNativeDelegate(env, delegate),
+      reinterpret_cast<gvr_context*>(gvr_api)));
 }
 
 }  // namespace vr_shell